Tension equalizer



y 14, 1963 A. E. GARDNER, JR 3,089,665

TENSION EQUALIZER Filed Nov. 9, 1960 5 Sheets-Sheet 1 .ZVVEN'T'UR 7. EEQ UNE L/ z May 14, 1963 A. E. GARDNER, JR

TENSION EQUALIZER 3 Sheets-Sheet 2 Filed Nov. 9, 1960 Q g N. a T V m T Filed Nov. 9, 1960 A. E. GARDNER, JR

TENSION EQUALIZER 3 Sheets-Sheet 3 a 5 [p 6,8" 0 0 0 1y INVE'N'TUR United States Patent 3,089,665 TENSION EQUALIZER Arthur E. Gardner, Jr., Wayne, N.J., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed Nov. 9, 1960, Ser- No. 68,273 1 Claim. (Cl. 242-156) This invention relates to tension equalizers, particularly tension equalizers for pairs of strands, or the like, pulled from separate supplies and wound simultaneously into packages.

In the manufacture of multi-unit cables, it is desirable to use pairs of binding ribbons of different colors to identify the cable units. To accomplish this result, each pair of ribbons of the desired colors must be taken from their initial supplies and wound into a single package so that the pair of ribbons may be removed, as in a binding unit, and wrapped simultaneously at spaced or side by side positions about their respective cable unit. This presents problems which arise in attempting to form packages of the pairs of ribbons where the ribbons are laid side by side with even or uniform tensions in the ribbons. To overcome conditions which result from unequal tensions, such as the existence of loops in one or the other of the ribbons causing uneven laying of the ribbons in the package, and the possible snagging of the loose ribbon during the binding operation, tension equalization is most important. These undesired results originate in the pulling of the ribbons from their supplies which may be of diiferent sizes, tending to create uneven tensions in the ribbons flowing from the supplies to the package being formed thereof.

The object of the invention is a tension equalizer capabio of maintaining predetermined like tensions in pairs of strands advanced from supplies to a take-up.

In accordance with the object, the tension equalizer tor a pair of strands pulled from separate supplies and wound simultaneously into a package on a rotating arbor comprises shafts for the supplies which have brakes applying predetermined forces to the shafts to create desired tensions in the strands and an element, having pulleys over which the strands travel in opposing directions toward the arbor, caused to rock by the influence of unbalanced tension in the strands, to cause operation of the brakes to increase the braking force on the strand of decreased tension, and to decrease the braking force on the strand of increased tension to thereby equalize the ten sions in the strands.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic front elevational view of one specie of the invention;

FIG. 2 is a fragmentary vertical sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a schematic illustration of another specie of the invention; and

FIG. 4 is a schematic illustration of the specification shown in FIG. 3 including also the travel of the strands from their supply spools to the winding arbor and the intermediate pulleys.

Considering the specie of the invention, illustrated in FIG. 1, the apparatus includes spaced shafts and 11 supported for rotation in any suitable manner, not shown, and adapted to receive supplies 12 and 14 of strands or the like. In the present instance, the supplies 12 and 14 are packages of polyethylene binder ribbons of dilferent colors, cores 15 and 16 of which are removably but firmly mounted on their shafts 10 and 11 so that, as the ribbons are pulled from the supplies, the shafts will be 3,089,665 Patented May 14, 1963 rotated. The shafts are provided with brake drums 17 and 18 which, in turn, are provided with braking elements which, in the present instance, are brake bands 19 and 20.

An element 22 mounted on a spindle 23 is positioned between the shafts 10 and 11 and provided with a pair of rotatable pulleys 24 and 25 at the ends thereof, about which the strands or ribbons 26 and 27 from the supplies 12 and 1-4 may pass in approaching an arbor 28 on which the ribbons are wound into the form of a package 29. There are additional pulleys, including a single pulley 30 and double pulleys 31, 32, and 33 for guiding the ribbons and their advance from the supplies to the arbor. Actually, the pulleys 32 and 33 form a capstan drive unit, the pulley or roller '32 being of rubber or the like and the drive pulley or roller 33 being of steel and forced toward the pulley 32 to constitute the pulling means for the ribbons. It will be observed that the ribbons 26 and 217, when leaving their supplies 12 and 14, approach the pulleys 24 from opposing directions to thereby tend to apply opposing forces to the lower end of the element 22 which would result in rocking the element from its given position, illustrated in FIG. 1, in a direction controlled by the ribbon of greatest tension.

This action is multiplied, or in a sense doubled, as the ribbons 26 and 27 reverse their directions of travel about the upper pulleys 25 and travel outwardly in opposing directions to their pulleys 30 and 31. Therefore, if the tensions in the ribbons or strands 26 and 27 are equal, the forces applied at both ends of the elements 22 are equalized and the element will remain in its given position. However, if, for example, tension in the ribbon 26 is greater than that in the ribbon 27, there will be an unbalanced pulling force at both ends of the element 22 resulting in rocking of the element clockwise.

A gear 35 is fixed to the spindle 2'3 and is rotated by the element 22 when an unbalanced tension exists in the strands or ribbons, otherwise, the gear remains stationary with the element 22 in the given position. A smaller gear or pinion 36, mounted on a shaft '37, is driven by the gear 35 when rotated in either direction. The ends of the brake band 19 are secured at 39 and 40 to the opposing ends of a lever 41. The lever 41 may be pivoted at 39, if desired, but for the purpose of illustration, a separate pivot 42 is provided for the lever.

A substantially identical structure is provided for the brake band 20 in that the ends of the brake band are secured at 43 and 44 to opposite ends of a lever 45 which is pivotally mounted at 46. A singleactuator 48 having its ends connected to the levers 41 and 45 at 40 and 43, respectively, has its central portion connected at 49 at an off center position to the gear 36. As a result, rocking movement of the element 22, by an unbalanced tension condition in the strands, will result in variation of the brake forces applied to the strands or ribbons to their supplies to equalize the tensions and to return the element 22 to its given position.

Operation Initially, the apparatus is provided with the supplies 12 and 14 mounted on their respective shafts 10 and 11 where their strands or ribbons are threaded in the manner shown. Throughout the threading of the ribbons, they are laid side by side, as illustrated in FIG. 2, by the provision of pairs of pulleys, in each instance, with exception of the pulley 30 where only a single pulley is re qu-ired for the ribbon 26. Therefore, the ribbons lay side by side in controlled paths as they are laid on the arbor and are built up into a package of the pairs of ribbons of different colors. When the apparatus. is set in motion, with the pre-adjusted brakes creating predetermined tensions in the ribbons, the ribbons are pulled from their supplies and caused to travel in the paths illustrated by the pulleys. Any variation in tensions in the ribbons, such as a decrease from the desired tension in one ribbon, or the increase from the desired tension in a ribbon creating an unbalanced condition, will result in the rocking of the element 22 by the ribbon having the greatest tension to rock the spindle 23 and the gear in one direction, and to rock or rotate the gear 36 in the opposite direction to cause the actuator 43 to rock the levers 41 and 45 simultaneously in like directions about their pivots 42 and 46. This simultaneous action on the brakes results in the decreasing in the braking force on the supply of the ribbon having the greater tension and the increasing of the braking force on the supply of the ribbon having lesser tension, thereby equalizing the tensions in the ribbons, resulting in the return of the element 22 to its given position and the return of the brake controlling means to its normal position to again apply equal braking forces on the supplies resulting in equal tensions in the ribbons.

The specie shown in FIGS. 3 and 4 utilize a portion of the structure shown in FIG. 1 including the rocking element 22, its spindle 23, its pulleys 24 and 25, the pulleys 30, 31, 32, and 33 and the arbor 28 to form the package 29. The supplies 12 and 14 are also the same. These figures illustrate the difference between the specie illustrated in FIG. 1 and that for the electrical control tension equalizer as compared to the mechanically controlled equalizer of FIG. 1.

In FIGS. 3 and 4 shafts 56 and 51 for the supplies have brake drums 52 and 53 which are under the control of electro-rnagnetic brakes 54 and 55. In this instance, the element 22, under the control of the ribbons, is held in a given position when the tensions in the ribbons are equal but is rocked as a result of unbalanced tensions. In place of gears and mechanical means actuated by the spindle 23, rheostats 56 and 57 are mounted so that their contacts 58 and 59 are rotated with the spindle. Here the rheostats are mounted in reverse order and normally located at their center positions to create a desired braking force in each brake 54 and and to increase or decrease these braking forces as a result of rocking movements of the spindle 23 resulting from unbalanced tensions in the ribbons to returns the spindle to its given position with the element 22 and to return the braking units, or rather equalize their braking forces. In this illustration, supply lines 60 and 61 energize a primary Winding 62 of avariable transformer 63. From the secondary winding 64, there are two circuits, one extending from connection 65 through a rectifier 66, rheostat 56, brake 54, back through rectifier 66 and connection 67.

The variable transformer is set with the setting of the rheostats 56 and 57 to create like predetermined braking forces in the brakes 54 and 55 to create uniform tensions in the strands or ribbons pulled from the sup-plies and rorating the shafts 50 and 51. The same action illustrated in FIG. 1, causing rocking of the element 22 in one direction or the other as the result of unbalanced tensions in the ribbons, will, in the specie shown in FIGS. 3 and 4, rock the spindle 23 to rock the rheostat contacts 58 in like directions as the result of unbalanced tension to vary the forces of the brakes 54 and 55 to overcome this unbalanced condition, to equalize the tensions in the ribbons, and to result in returning the spindle 23 with the element '22 to its given position.

It is to be understood that the above described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

A device for maintaining a condition of equal tension in first and second strands advancing simultaneously from separate supply spools onto a common arbor, a first shaft for supporting one of the supply spools, a second shaft mounted parallel to said first shaft and laterally spaced therefrom for supporting the other of said supply spools spaced from said one of the supply spools, a rocking element mounted for rotation on an axis parallel to and between said first and second shafts in a plane defined by said first and second shafts, :a first pair of pulleys mounted for rotation at one end of the rocking element for receiving the first and second strands advancing in opposite directions from the spaced supply spools, a second pair of pulleys mounted for rotation at the other end of said rocking element for guiding the first and second strands leaving said first pair of pulleys to form an acute angle with respect to the first and second strands advancing in said opposite directions from the spaced supply spools, a first guide pulley mounted on the same side of said element as said second shaft and spaced from said second shaft for guiding said first strand around one pulley of said second pair of pulleys in a first preselected direction, a second guide pulley mounted on the same side of the element as said first shaft and spaced from said first shaft for guiding said second strand around the other pulley of said second pair of pulleys in a second preselected direction divergent from said first preselected direction, means for drawing said first and second strands simultaneously from said separate supply spools around said respective pulleys onto said common arbor, a rotary spindle mounting said rocking element intermediate the ends thereof, said spindle rotated by the element upon occurrence of an unequal condition between the tension in the first and second strands advancing in said opposite and divergent directions, selectively operable electromagnetic brake means for retarding the rotation of a selected one of said first and said second shafts and releasing a selected other of said first and second shafts to maintain said condition of equal tension, and rheostat means rotated by said rotary spindle upon occurrence of said unequal tension condition for controlling said selectively operable electromagnetic brake means to restore said condition of equal tension.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain OTHER REFERENCES German application 1,062,299, printed July 30, 1959, (K1. 21C 4/02). 

